I have an x100VI with 1.01 firmware - did a reset already and didnt solve issue I am about to describe. Can you all see if your camera does this: Switch to C mode, step down to f16 and then press shutter half way. Does your screen go dark? I have tried playing will all settings (have had the following so quite familiar with the menus: x100, x100f, XT-2, X-Pro 2, XT-3) , only happens in C mode. If you find this can you report to Fuji @ digitalinfo@fujifilm.com. They told me they had not seen this before and that it was normal behavior because the shutter is closing, but the shutter closes in S mode as well.

That’s a common problem with many cameras, filters irritating the autofocus.

I can't vouch for the Sigma on the X-S20 but I do have a Viltrox (27mm f/1.2) and the startup speed is identical to when I have the Fuji 18-55 on it.

I have focus error issues when I placed a VU filter on the X100VI. Only on close up macro photography. The filter is placed backwards because of the threading. When I take the filter off the camera the focus works properly. 

In Windows PCs the backup is saved in  folder Documents>Fujifilm>Conditions. If you open this folder in a window before you start the backup you'll see the backup file appear in the window. It's almost instantaneous. It's a confidence booster. I don't remember X-Aquire giving any indication that backup has completed. The backup files include the date and the camera make so if you have two Fuji cameras they all go in the same folder. New backups do not over-write the older ones so you can restore an older one if you should so wish. Simon